Adhesive interactions among leukocytes and between leukocytes and endothelium are central to processes of inflammation.These interactions are mediated by sequential molecular steps involving carbohydrates and selectins, and integrins and ICAMs. We are presently using flow cytometry to examine the interaction of neutrophils with cells transfected with ICAM, a counter structure for the neutrophil integrins. A manuscript is in preparation for submission to J. Immunol. Next year we will extend this approach to exmaine the mechanisms of aggregation of lymphoma cells which may contribute to leukostasis.